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Current Approaches Origin Authentication –Dynamic Security Skins [DhamTyga 2004], Passmark, and the Petname project –All rely on user diligence – a single mistake will result in a compromised account

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Key Insight Security must not depend entirely on fallible users System must be secure by default Design must be robust to user error

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Phishing Prevention Goals Ideal: User’s data only reaches intended recipient Practical: Prevent a phisher from viewing or modifying a user’s accounts –Reduce the power of attacks to that of pre- Internet scams E.g., an attacker can still subvert a company insider

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Contributions Plan for human errors by guarding users’ accounts even when they make mistakes Use a mobile device to establish an authenticator the user cannot readily disclose Protect against active Man-in-the-Middle attacks Defend against keyloggers Develop a prototype implementation

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Phoolproof Prevention Overview Mobile device creates a public key pair for each site –Transmits public key to the server To access the site, the mobile device uses the private key to authenticate to the server –Assists browser in establishing SSL/TLS session Server refuses access unless client can provide user’s password and the mobile device authenticates properly

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Advanced Phoolproof Setup For additional security, establish a shared secret via a trusted side-channel –Mail a nonce (or barcode) to address on file –Display a barcode at an ATM –Setup in person Trusted financial institutions could provide setup for companies without a storefront The problem of properly identifying new customers predates the Internet Existing research can help secure setup

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Security Analysis Malware on the computer –Standard keylogger fails, since it only obtains password –Compromise of the browser or the operating system is still a problem Attacks on the network –Our system is immune to Man-in-the-Middle attacks, pharming attacks, and domain hijacking Local attacks on Bluetooth –Phishing relies on large-scale attacks, not local attacks –Attacker still lacks user’s password, so account is secure –Existing research [McCune et al. 2005] demonstrates how to establish a secure channel

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Conclusions Phishing is a growing problem, and attacks will only become more sophisticated We should avoid relying on perfect user behavior Instead, we use cryptographic techniques to protect even fallible users Our implementation demonstrates the feasibility of phoolproof phishing prevention

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Thank you!

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Future Work Expand prototype into a fully robust application Perform a user study to assess ease of use Integrate with our university’s web login Collaborate with other institutions

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Man-in-the-Middle Attack Immune to this attack for the same reason SSL/TLS is immune: Attacker does not have access to the private key material for the user or the server